Yemen's Defense Ministry says soldiers have entered an al-Qaeda stronghold in the country's south, one of the main goals of the major offensive launched by the military in the last two weeks.

The ministry says troops captured the center of the district of Azzan on Thursday. Fighting continued in the mountains surrounding the district. In the past, government offensives have sparked retaliatory attacks, suicide bombings and mass killings targeting mainly police and the military.

Meanwhile, officials say the US has closed its embassy in Yemen temporarily -- but didn't cite specific threats to Americans.

Yemeni officials said that the embassy closed its offices starting Tuesday, a day after gunmen opened fire on three French security guards working with the European Union mission, killing one and wounding another. (AP)